为了研究汶川地震中一处双级加筋土挡墙的破坏机理,利用FLAC3D有限差分软件进行动力分析；在此基础上,研究平台宽度的变化对双级加筋土挡墙抗震性能的影响。数值结果表明：汶川地震中,平台位置产生过大的水平位移和竖向位移是该双级加筋土挡墙发生局部破坏的原因；地震作用下,墙顶处水平位移最大值与不同的平台宽度之间呈非线性关系,上级挡墙的水平位移最大值随平台宽度的增加先减小后增大,而下级挡墙的水平位移最大值则随平台宽度的增加先增大后减小；增大平台宽度可以减小下级挡墙面板附近填土的竖向位移；在低烈度时,平台宽度对峰值加速度( Peak Ground Acceleration, PGA)放大系数影响较小；在高烈度时,平台宽度对PGA放大系数影响较大。因此通过设计合理的平台宽度能提高双级加筋土挡墙抗震性能。%Dynamic analysis was conducted with FLAC3D to study the failure mechanism of a two-stage reinforced soil-retaining wall in Wenchuan earthquake. On this basis, the effect of platform width on the seismic performance of the wall was researched. The numerical results reveal that too large horizontal and vertical displacement at the platform is the cause of local failure of the wall. Under seismic action, the maximum horizontal displacement at the top of the wall is in a non-linear relationship with the platform width, and the maximum horizontal displacement of the upper wall firstly decreases with the increase of platform width and then increases;while the horizontal displace-ment of the lower wall firstly grows with the increase of platform width and then decreases. Vertical displacement of backfill near by the lower wall panel could be reduced by increasing the platform width. Moreover, under low seis-mic intensity, platform width has no apparent effect on the magnification of PGA ( Peak Ground Acceleration) but in the opposite under high intensity. Therefore, the seismic performance of two-stage reinforced soil retaining wall could be improved by designing a reasonable platform width.
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